1. Field of the Invention
The present invention relates to a computer construction and more particularly to a printed circuit card construction used therein.
2. Description of the Prior Art
In recent years, the scale of the computer system has become considerably large. Therefore, the conventional IC (Integrated Circuit) and LSI (Large-Scale Integrated Circuit) are not sufficient for constructing each unit of logic circuits used in the large-scale computer system. Accordingly, an LSI having a great number of gate-circuits such as an ultra-LSI is very useful for constructing each unit of logic circuits used in such large-scale computer systems. In the large-scale computer system which is constructed by mounting a large number of ultra-LSIs on the printed circuit cards, an efficient printed circuit card construction must be employed therein.
In the prior art, there are two different kinds of printed circuit card constructions: firstly, the so-called shelf-type printed circuit card construction and, secondly, the printed circuit card construction which was disclosed in the U.S. Pat. No. 3,903,404. However, the two above-mentioned printed circuit card constructions have the following defects. The shelf-type construction has the defect wherein the total number of I/O (Input/Output) pins printed on one side of each printed circuit card is very small as compared to the total number of gates included in the ultra-LSIs being mounted on each printed circuit card. Regarding the latter construction of the U.S. Pat. No. 3,903,404, it has the following defect that, although this construction can overcome the defect of the above-mentioned shelf-type construction, the total length of the lead wires which electrically connect ultra-LSIs mounted on one printed circuit card with cooperating ultra-LSIs mounted on another printed circuit card is extremely increased.